So-called power and free conveyor systems play a major role in automotive and other manufacturing facilities for transport of heavy components and assemblies. Conveyors of this type include trolley frames having spaced pairs of load wheels supporting the carrier for longitudinal motion along a track, and a spaced pair of guide wheels for engaging the track and maintaining orientation of the trolley frame with respect to the center of the track. Missing or damaged load or guide wheels can cause the trolley to become jammed in the track, resulting in significant downtime for maintenance and repair. In automotive paint system applications, for example, jamming of a trolley carrier within a paint oven not only results in significant downtime while waiting for the oven to cool, but also can significantly increase the scrap rate of components and parts in the paint preparation process upstream of the oven.
It is therefore a general object of the present invention to provide a system for monitoring the integrity of the load and guide wheels on a trolley frame during operation of the conveyor system to indicate missing or damaged wheels in real time, and thereby help prevent conveyor downtime in a mass production manufacturing environment.
A trolley conveyor system includes a trolley frame which has spaced pairs of load wheels supporting the trolley frame for movement in a longitudinal direction along a track and a spaced pair of guide wheels to maintain alignment of the trolley with respect to the center of the track. The present invention provides a system for monitoring operative condition of the trolley carrier load and guide wheels. A pair of first sensors are respectively disposed on opposed sides of the track, and are responsive to sequential passage of a corresponding pair of load wheels for generating first electrical signal patterns as a function thereof. A plurality of second sensors are mounted adjacent to the track and responsive to passage of the pair of guide wheels for generating second electrical signal patterns as a function thereof. A fundamental mode asynchronous machine performs pattern recognition analysis on the first and second signal patterns to determine operative condition of the load and guide wheels in real time.